Measure cached Dosh attach fast path

src/bin/dosh-bench.rs

@@ -40,6 +40,10 @@ struct Args {
     #[arg(long)]
     no_cache: bool,
     #[arg(long)]
+    warm_cache: bool,
+    #[arg(long)]
+    skip_ssh_baseline: bool,
+    #[arg(long)]
     include_mosh: bool,
     #[arg(long, default_value = "mosh")]
     mosh: PathBuf,
@@ -51,6 +55,8 @@ struct Args {
     assert_ssh_plus_ms: Option<f64>,
     #[arg(long)]
     assert_mosh_minus_ms: Option<f64>,
+    #[arg(long)]
+    assert_dosh_max_ms: Option<f64>,
 }
 
 fn main() -> Result<()> {
@@ -72,46 +78,25 @@ fn main() -> Result<()> {
     } else {
         None
     };
+    if args.no_cache && args.warm_cache {
+        return Err(anyhow!("--warm-cache cannot be used with --no-cache"));
+    }
+    let dosh_label = if args.warm_cache {
+        let _ = time_dosh_attach(&client, &args, control_path)?;
+        "dosh_cached_attach_ms"
+    } else {
+        "dosh_attach_ms"
+    };
 
     for _ in 0..args.iterations.max(1) {
-        if !args.local_auth {
+        if !args.local_auth && !args.skip_ssh_baseline {
             let mut ssh = Command::new("ssh");
             add_ssh_options(&mut ssh, &args, control_path);
             ssh.arg(&args.server).arg("true");
             ssh_times.push(time_command(&mut ssh)?);
         }
 
-        let mut cmd = Command::new(&client);
-        cmd.arg("--attach-only")
-            .arg("--session")
-            .arg(&args.session)
-            .arg("--dosh-port")
-            .arg(args.dosh_port.to_string());
-        if let Some(host) = &args.dosh_host {
-            cmd.arg("--dosh-host").arg(host);
-        }
-        if args.local_auth {
-            cmd.arg("--local-auth").arg(&args.server);
-        } else {
-            cmd.arg("--ssh-port")
-                .arg(args.ssh_port.to_string())
-                .arg("--ssh-auth-command")
-                .arg(&args.ssh_auth_command);
-            if args.no_cache {
-                cmd.arg("--no-cache");
-            }
-            if let Some(key) = &args.ssh_key {
-                cmd.arg("--ssh-key").arg(key);
-            }
-            if let Some(known_hosts) = &args.ssh_known_hosts {
-                cmd.arg("--ssh-known-hosts").arg(known_hosts);
-            }
-            if let Some(control_path) = control_path {
-                cmd.arg("--ssh-control-path").arg(control_path);
-            }
-            cmd.arg(&args.server);
-        }
-        dosh_times.push(time_command(&mut cmd)?);
+        dosh_times.push(time_dosh_attach(&client, &args, control_path)?);
 
         if args.include_mosh {
             mosh_times.push(time_mosh_in_pty(&args)?);
@@ -126,7 +111,7 @@ fn main() -> Result<()> {
         );
     }
     println!(
-        "dosh_attach_ms avg={:.2} samples={:?}",
+        "{dosh_label} avg={:.2} samples={:?}",
         avg_ms(&dosh_times),
         dosh_times
     );
@@ -167,9 +152,56 @@ fn main() -> Result<()> {
         }
         println!("gate ok: dosh avg {dosh_avg:.2}ms + {margin:.2}ms <= mosh avg {mosh_avg:.2}ms");
     }
+    if let Some(max_ms) = args.assert_dosh_max_ms {
+        let dosh_avg = avg_ms(&dosh_times);
+        if dosh_avg > max_ms {
+            return Err(anyhow!(
+                "{dosh_label} avg {dosh_avg:.2}ms exceeded max {max_ms:.2}ms"
+            ));
+        }
+        println!("gate ok: {dosh_label} avg {dosh_avg:.2}ms <= {max_ms:.2}ms");
+    }
     Ok(())
 }
 
+fn time_dosh_attach(
+    client: &PathBuf,
+    args: &Args,
+    control_path: Option<&PathBuf>,
+) -> Result<Duration> {
+    let mut cmd = Command::new(client);
+    cmd.arg("--attach-only")
+        .arg("--session")
+        .arg(&args.session)
+        .arg("--dosh-port")
+        .arg(args.dosh_port.to_string());
+    if let Some(host) = &args.dosh_host {
+        cmd.arg("--dosh-host").arg(host);
+    }
+    if args.local_auth {
+        cmd.arg("--local-auth").arg(&args.server);
+    } else {
+        cmd.arg("--ssh-port")
+            .arg(args.ssh_port.to_string())
+            .arg("--ssh-auth-command")
+            .arg(&args.ssh_auth_command);
+        if args.no_cache {
+            cmd.arg("--no-cache");
+        }
+        if let Some(key) = &args.ssh_key {
+            cmd.arg("--ssh-key").arg(key);
+        }
+        if let Some(known_hosts) = &args.ssh_known_hosts {
+            cmd.arg("--ssh-known-hosts").arg(known_hosts);
+        }
+        if let Some(control_path) = control_path {
+            cmd.arg("--ssh-control-path").arg(control_path);
+        }
+        cmd.arg(&args.server);
+    }
+    time_command(&mut cmd)
+}
+
 fn add_ssh_options(cmd: &mut Command, args: &Args, control_path: Option<&PathBuf>) {
     cmd.arg("-p").arg(args.ssh_port.to_string()).arg("-T");
     if let Some(key) = &args.ssh_key {